The present invention generally relates to semiconductor manufacturing and, more particularly, relates to heat spreader lids and package assemblies including a heat spreader lid.
Industry practice in the field of semiconductor packaging is to mount a semiconductor chip or chip stack to a package substrate composed of a laminate or organic material, such as an epoxy resin. The chip or chip stack generates heat when powered in operation. Thermal management of the package may require some type of thermal management mechanism mounted to the chip or chip stack to extract and dissipate the generated heat. Absent effective heat dissipation, the generated heat can reduce chip performance, decrease reliability, and reduce the useful lifetime of the chip.
One type of thermal management solution is a heat spreader lid disposed in thermal contact with an exterior surface of the semiconductor chip or chip stack. Conventional heat spreader lids have a solid, continuous surface with uniform thickness. This surface of the heat spreader lid may be adhered to the chip with a thermally conductive layer of material. The heat spreader lid may also include a flange that is adhered to the substrate with an adhesive, which may be electrically conductive.
As the size of the semiconductor chip and the substrate increase such that the package size increases, the package may become increasingly prone to warpage, cracking and delamination due to thermal and mechanical stress at the chip-to-package interface. In particular, cracking may be observed at and near the corners of the packaged chip.
Improved heat spreader lids and package assemblies including a heat spreader lid are needed.